This invention relates to a cylindrical lock assembly and particularly to a cylindrical lock assembly having cassettes of uniform construction for interchangeability.
In conventional lever lock set assemblies, the spring of the cassette on one side of the door, for example the inside, must be wound in a dedicated fashion in comparison to the spring on the other side of the door in order to compress the spring upon operation of the associated lever. Further, all mounting screws are typically mounted from the inside of the door and are threadedly fastened into threaded holes in the cassette mounted on the outside of the door.
When a user wishes to reverse the inside-outside arrangement of the door, the cassettes must be disassembled to remove the springs for reassembly in their respective dedicated locations of inside and outside the door. In addition, for security reasons, the two mounting screws must always enter the assembly from inside the door to prevent unauthorized dismantling of the assembly from outside the door. Therefore, the cassettes must be disassembled so that the housing of the cassette which was originally inside the door will remain in that location after the reversing procedure has been completed.
Due to the arrangement of the components within the cassette, including the preloading of the springs, it is a difficult and tedious task to disassemble and reassemble the cassettes at the user site.
Thus, there is a need for a spring cassette of generally universal construction which can be interchanged with the cassette on the opposite side of the door when reversing the inside-outside arrangement of the door without removal of the spring from the cassette housing.